A motion guide device having a rolling element such as a ball, a roller, or the like acting to mediate as a mechanical element for guiding linear or curved motion of a moving body such as a table or the like in a guide portion of the motion guide device allows nimble movement to be achieved and is therefore utilized in various fields such as those of robots, machine tools, semiconductor and liquid crystal manufacturing devices, medical equipment, and so on.
A linear guide which is one kind of motion guide device comprises a track rail attached to a base and a moving block assembled in a relative-motion-enabling manner on the track rail and being attached with a moving body. A rolling element rolling unit is formed in the track rail, the rolling element rolling unit extending along a longer direction of the track rail. A load rolling element rolling unit opposing the rolling element rolling unit is formed in the moving block, and a rolling element circulation path for circulating rolling elements is also provided in the moving block. The rolling elements are arranged in a freely rolling manner between a ball rolling unit in the track rail and a load ball rolling groove in the moving block. When the moving block performs linear motion relatively to the track rail, the rolling elements arranged between the track rail and the moving block move by rolling and the rolling element circulation path circulates.
When using this kind of rolling type motion guide device, good lubrication is required, that is, it is required to create a film of oil between the rolling elements and a rolling surface, and prevent metal and metal making direct contact. This is because if the device is used as is without oil being supplied, friction between the rolling elements and the rolling surface increases resulting in a short operating life.
Various kinds of systems exist among methods of lubricant oil supply in the motion guide device. One such system has oil supply performed via a greasing nipple attached to the moving block of the motion guide device. Generally, the greasing nipple is attached to end plates attached to both of front and rear end surfaces of the moving block, and a lubricant supply path linking this greasing nipple and the rolling element circulation path is formed in an interior of the moving block and a side contacting an end surface of the moving block, and when a lubricant of oil, grease or the like is supplied to the greasing nipple, the lubricant is coated on the rolling elements via the lubricant supply path.
The lubricant supply path formed in the end plates is required to divide supply of the lubricant uniformly among multiply-existing rolling element circulation paths, and, for example, Patent Document 1 mentioned below discloses a configuration in which a plurality of lubricant supply paths respectively linking a greasing nipple and each of rolling element circulation paths are formed to be substantially uniform regarding the likes of shape, formation position, and path length. Patent Document 1 mentioned below, by the plurality of lubricant supply paths having a substantially uniform configuration, allows supply of the lubricant to be divided averagely among each of the rolling element circulation paths, whereby appropriate lubrication is realized.
Incidentally, an attachment position of the greasing nipple attached to the end plates requires to be changed arbitrarily in response to conditions of use of the motion guide device, peripheral environment, and so on, specifically, it is required to configure such that mounting can be performed at front and rear ends, left and right side surfaces and so on in a moving direction of the moving block with respect to the track rail. Accordingly, the conventional technology represented in the likes of Patent Document 1 mentioned below also has an oil-injection hole formed in a front surface, left and right side surfaces, and so on of end plates, and adopted a configuration such that the greasing nipples can be mounted with respect to the oil-injection hole at these arbitrary positions.